Acrylamide exposure from foods of the Dutch population and an assessment of the consequent risks.

At the end of April 2002, the Swedish Food Administration reported the presence of acrylamide in heat treated food products. Acrylamide has been shown to be toxic and carcinogenic in animals, and has been classified by the WHO/IARC among others as 'probably carcinogenic for humans'. The purposes of this study were firstly to analyse acrylamide contents of the most important foods contributing to such exposure, secondly, to estimate the acrylamide exposure in a representative sample of the Dutch population, and thirdly to estimate the public health risks of this consumption. We analysed the acrylamide content of foods with an LC-MS-MS method. The results were then used to estimate the acrylamide exposure of consumers who participated in the National Food Consumption Survey (NFCS) in 1998 (n=6250). The exposure was estimated using the probabilistic approach for the total Dutch population and several age groups. For 344 food products, acrylamide amounts ranged from <30 to 3100 microg/kg. Foods with the highest mean acrylamide amounts were potato crisps (1249 microg/kg), chips (deep-fried) (351 microg/kg), cocktail snacks (1060 microg/kg), and gingerbread (890 microg/kg). The mean acrylamide exposure of the NFCS participants was 0.48 microg/kg bw/day. Risk of neurotoxicity is negligible. From exposure estimations it appears that the additional cancer risk might not be negligible.

[Biotechnology, especially genetic modification, and legislation]. / Biotechnologie, met name genetische modificatie, en de wetgeving.

Biotechnology and genetic modification (GM) related legislation is not yet fully developed in the European Union (EU). New legislation has been recently issued ('Introduction of GMO's in the environment') and recently proposals from the European Commission ('GMO's in food and feed' and 'Traceability and labelling of GMO's') entered the decision-making process in the end of 2001. The proposals for the establishment of the European Food Authority play a role in this respect. GMO legislation is complex not in the least because of the demands for the dossiers, to be submitted with an application, while these procedures for admission must become more transparent. In this paper the relevant legislation will be discussed with the exception of that related to human health. Because of dissatisfaction with the present legislation, the European Commission in the past years granted no new approvals for introductions on the market of GMO's and for GM novel foods. New legislation should suspend the present de-facto moratorium. The tasks and position of the Inspectorate for the Health Protection and Veterinary Public Health is discussed. A provision has been made in the legislation with respect to adventitious or technically unavoidable contamination of raw materials with GMO's up to a maximum of 1%, of which the enforcement is not yet watertight. The analytical methods are being still developed.

[An epidemic of epileptic seizures after consumption of herbal tea]. / Een epidemie van epileptische aanvallen na drinken van kruidenthee.

UNLABELLED: At the end of September 2001 the Inspectorate for Health Protection and Veterinary Public Health and the National Poisons Control Centre (NPCC) were informed about adverse health effects after consumption of a herbal tea. During consultations it was suggested that Japanese star anise (Illicium anisatum L.), which is known to contain a neurotoxin, may have been inadvertently mixed into the herbal tea. In view of the severity of the adverse health effects and the clear association with consumption of a specific herbal tea, the supplier was urgently advised to withdraw the suspected herbal tea from the market. A total of 63 persons reported symptoms of general malaise, nausea and vomiting 2-4 hours following consumption of the herbal tea. Twenty-two persons required hospitalisation, of whom 16 due to generalised tonic-clonic seizures. Medical investigations revealed no underlying pathology and after supportive treatment, the patients were discharged in good health. Morphologic and organoleptic investigations of the suspected herbal tea indicated that this possibly contained Japanese star anise. NMR analysis of the herbal tea confirmed the presence of the neurotoxin anisatin, a non-competitive GABA-antagonist which can cause hyperactivity of the central nervous system and tonic-clonic seizures. CONCLUSION: Ingestion of a herbal tea containing anisatin caused the reported serious adverse health effects. Close cooperation between clinicians, the Inspectorate for Health Protection and Veterinary Public Health and the NPCC played a vital role in preventing further harm to public health.

Developmental toxicology: adequacy of current methods.

Toxicology embraces several disciplines such as carcinogenicity, mutagenicity and reproductive toxicity. Reproductive toxicology is concerned with possible effects of substances on the reproductive process, i.e. on sexual organs and their functions, endocrine regulation, fertilization, transport of the fertilized ovum, implantation, and embryonic, fetal and postnatal development, until the end-differentiation of the organs is achieved. Reproductive toxicology is divided into areas related to male and female fertility, and developmental toxicology. Developmental toxicology can be further broken down into prenatal and postnatal toxicology. Today, much new information is available about the origins of developmental disorders resulting from chemical exposure. While these findings seem to promise important new developments in methodology and research, there is a danger of losing sight of the precepts and principles established in the light of existing knowledge. There is also a danger that we may fail to correct shortcomings in our existing procedures and practice. The aim of this presentation is to emphasize the importance of testing substances for their impact in advance of their use and to underline that we must use the best existing tools for carrying out risk assessments. Moreover, it needs to be stressed that there are many substances that are never assessed with respect to reproductive and developmental toxicity. Similarly, our programmes for post-marketing surveillance with respect to developmental toxicology are grossly inadequate. Our ability to identify risks to normal development and reproduction would be much improved, first if a number of straightforward precepts were always followed and second, if we had a clearer understanding of what we mean by risk and acceptable levels of risk in the context of development. Other aims of this paper are: to stress the complexity of the different stages of normal prenatal development; to note the principles that are applicable in developmental and especially prenatal toxicology; to describe the different agents that might act as developmental toxicants or teratogens; to show the broad scope of different effects caused by developmental toxic agents; and to indicate methods to detect and to recognise causes of developmental defects with the primary objective of preventing these disorders.

Heterogeneity of spina bifida.

Splitting birth defects into dysmorphologically homogeneous groups might improve the ability to detect a genetic risk factor or teratogenic exposure. With regard to spina bifida, recent studies suggest that etiologic heterogeneity exists within the group of spina bifida, although exogenous risk factors have been sparsely evaluated for subgroups. In the present study, 210 spina bifida patients were classified into relatively homogeneous groups, based on retrospective information on appearance and functional aspects of the lesion abstracted from medical records of the patients. We compared high with low spina bifida, and open with closed spina bifida, and investigated whether risk factors for spina bifida such as maternal age, antiepileptic drug use, parental occupation, and genetic factors were specifically associated with these homogeneous subclasses. For these comparisons, a referent group of 671 children was used. Although classifying spina bifida into homogeneous subclasses presented some difficulties and numbers were small, this study provides some evidence for different risk profiles for subclasses of spina bifida. The sex ratio, the proportion of miscarriages of siblings, and maternal age did not differ among the different subclasses of spina bifida. However, children with a positive family history of neural tube defects (NTDs) had a higher risk of high spina bifida [odds ratio (OR) = 6.3, 95% confidence interval (CI): 1.7-19.2] than of low spina bifida (OR = 2.1, 95% CI: 1.0-4.2). Siblings with NTDs were more common in cases with high spina bifida and cases with open spina bifida. A strongly increased risk of high spina bifida was found for male welders (OR = 12.1, 95% CI: 1.5-64.2), whereas the risk of low spina bifida was much lower (OR = 1.6, 95% CI: 0.2-7.9). For mothers with agricultural occupations, a strongly increased risk was observed for open spina bifida (OR = 14.3, 95% CI: 2.9-77.7), whereas none of 107 cases with closed spina bifida had a mother with an occupation in agriculture. Due to small numbers, the results must be interpreted with caution.

Old paths retrodden.

Much new information is present about the origins of developmental disorders resulting from chemical exposure. However, there is a danger of losing sight of the precepts and principles established in the light of existing knowledge. Our ability to identify risks to normal development and reproduction would be much improved if a number of straightforward rules were always followed. This article proposes 10 precepts: do not neglect resorptions; use appropriate terminology; study pathogenetic mechanisms; strive to develop new models of evaluating data; slavish adherence to guidelines blocks informed ratiocination; do not forget the yolk sac; remember the adaptability of pregnant women; respect the environment of the unborn; avoid causing unnecessary alarm and do not confuse association with causation; and finally, always remember the human purpose for which tests on laboratory animals are performed. These tenets are emphasised in order that in pursuing new approaches and integrating new information we do not lose sight of existing knowledge.

Creutzfeldt-Jakob disease: results of an inquiry in the fifteen Member States of the European Union.

Creutzfeldt-Jakob Disease (CJD) was first described in 1920-1921. CJD is a rare disease with a reported incidence of 0.5 to 1 case per million people in Europe. This fatal dementia belongs to the category of Transmissible Spongiform Encephalopathies (TSE)

Effects of cadmium on reproduction, an epizootologic study.

The Dutch part of Kempenland has been exposed to cadmium pollution since the last century. Experimental data suggest effects by cadmium on reproduction such as diminished fertility, decreased foetal growth, and specific malformations. Use was made of a historical cohort of dairy cows, ascertained from a surveillance program conducted by the regional Veterinary Health Service between 1976 and 1986. Ten dairy farms in the cadmium region were matched by size with 40 dairy farms from a reference area. Logistic models were used to calculate Odds (OR) and Rate Ratios (RR) and their 95% confidence interval. In total 4,039 exposed and 15,552 reference gestations were compared. The reasons for the slaughter of 574 exposed and of 2,824 reference cows were ascertained. A lower twinning rate [OR = 0.63 (0.47-0.84)] was found and more birth complications, for both calves [OR = 1.50 (1.25-1.80)] and cows [OR = 1.49 (1.24-1.79)]. More inseminations [OR = 1.20 (1.01-1.43)] were needed for conception in the exposed area. Deaths among twins [OR = 1.66 (0.90-3.07)] were not significantly higher. Perinatal death, premature death, age at, or reasons for, slaughter were not consistently different. These results are consistent with those of other observational and experimental studies. Extrapolation from these large domestic animals to humans is problematic, as is the more frequent extrapolation from rodents to humans. It can be concluded that longterm exposure to low levels of cadmium is associated with impaired reproduction in dairy cows.

Risk assessment of drug use in pregnancy: prevention of birth defects.

Some developmental disorders are preventable by primary prevention, i.e. by avoiding exposure to microorganisms or chemicals that cause developmental disorders. This is not only important for physicians prescribing drugs, midwives monitoring pregnancies, but especially for parents taking the responsibility of having a baby; moreover, this fact is of importance for teratogen information services and public health authorities, both having preventive roles to play. Knowledge of the different pre- and postnatal developmental stages and the reproductive cycle is essential to understand this statement. The basic principle in reproductive toxicology and teratology is that the response of an organism to a teratogen depends upon the nature and the dosage of the substance, the stage of development of the embryo/fetus and its genetic make up. Chemical agents of different nature can induce developmental disorders either via the mother and perhaps via the father. The common consent that the vulnerable stage of development is only the first trimester of pregnancy is not correct. From oogenesis and spermatogenesis to at least the first years of life the developing organism is susceptible to harmful effects of chemical agents, including drugs. Developmental disorders include not only malformations visible at birth, but also spontaneous abortions, fetal death and functional deficits including behavioural defects. Studies both in the human and in laboratory animals make it possible to select substances to avoid exposure to developmental toxicants which are already on the market or still under development. This implicates a multi-step procedure leading from risk-evaluation, risk-assessment, and risk-communication to risk-perception and the according action (risk-management).

Intrauterine diethyltoluamide exposure and fetal outcome.

The CNS toxicity of the insect repellent, diethyltoluamide (DEET), has been documented by several publications on severely affected adults and children. We report a 4-year-old boy with mental retardation, impaired sensorimotor coordination, and craniofacial dysmorphology, whose mother applied DEET daily throughout her whole pregnancy in addition to the prophylactic use of chloroquine.

Biotransformation of cyclophosphamide in post-implantation rat embryo culture using maternal hepatocytes in co-culture.

The post-implantation rat embryo culture technique is employed to study embryotoxic effects of xenobiotic compounds in the absence of the maternal compartment. For compounds biotransformed in vivo the embryo culture technique must be adapted in order to mimick the in vivo effects. In the present study the possibility of co-culturing metabolically active maternal hepatocytes suspended in the standard culture system with rat serum as a medium was investigated. Cyclophosphamide (CP) was used as a model compound as it needs bioactivation to display embryotoxicity. Morphologic and histologic effects were studied. Neither hepatocytes nor CP alone affected embryo development, whereas in the presence of hepatocytes embryotoxicity was observed at 30 micrograms/ml CP. Embryotoxicity was decreased in the additional presence of metyrapone, a monoxygenase inhibitor. Hepatocyte suspensions prepared via slicing or perfusion of livers were equally effective. In conclusion, co-culture of embryos and suspended hepatocytes can be performed under optimal conditions for embryo development and in the presence of biotransforming activity.

Interlaboratory evaluation of three culture media for postimplantation rodent embryos.

The first aim of the study was to compare the ability of rat serum, human serum, and a mixture of human and rat serum (4:1) to support in vitro development of rodent postimplantation embryos. The comparison was made in three laboratories using rat embryos and in one laboratory using mouse embryos. Batches of sera, initial developmental stage, duration of culture, and endpoints were identical in the laboratories. The second aim of the study was to evaluate if other variables that could not be standardized would significantly influence the results of the laboratories. No reproducible difference was observed among the culture media or among the laboratories except that growth and differentiation were slower in the laboratory using mouse embryos. Further experiments are needed to exclude small differences in performance of the media.

Effects of low sodium concentrations on the development of post-implantation rat embryos in culture and on their sensitivity to anticonvulsants.

Anticonvulsant drug treatment during pregnancy is associated with an increased incidence of developmental disorders. The finding that anticonvulsant treatment can induce hyponatraemia prompted us to study the role of this parameter in the induction of malformations. Rats were treated orally with the anticonvulsants phenytoin, phenobarbitone, carbamazepine and valproic acid, and their sera were used as media in cultures of post-implantation (day 10) rat embryos. Sodium concentrations in the media were adjusted by mixing sera with 25% tissue-culture medium with or without sodium chloride. We found that low sodium concentrations caused retardation of development and enhanced the sensitivity of embryos to the retardant effects of anticonvulsants. These results show that apart from the direct effects of drugs and their metabolites secondary factors may be important in the aetiology of maldevelopment.

Experience of two teratology information services in Europe.

Teratology Information Services (TIS) are started in different countries in Europe in order to gather available data on exogenous agents, to evaluate their pertinence to human subjects, and to apply this knowledge to specific cases. Most European centers can only be consulted by medical professionals. The experience of two such services (Lyon, France, and Bilthoven, The Netherlands) is described. Attention is given to the task of TIS, risk evaluation, operational methods, and functioning and future developments.

A study of drug utilization in pregnancy in the light of known risks: is there room for improvement?

The prescription records of 1948 Dutch women who delivered a live-born infant during an 18 month period in 1987 and 1988 were set against the Australian classification of drugs with respect to the known or suspected risks in pregnancy. During pregnancy the use of drugs with proven or anticipated foetal toxicity proves to decrease, indicating that the medical profession is relatively well aware of these potential side effects. In the case of antibiotics the fall in the use of potentially toxic drugs is due to a shift to relatively less toxic drugs whereas the decreased use of analgesics and some antirheumatic drugs is not accompanied by replacement by others. Prescriptions for hormonal contraceptives were sometimes actually filled in the first trimester of pregnancy, and the figures suggest that exposure to these products in early pregnancy may not be negligible. The present study shows that in spite of the generally favourable trends, 167.8 out of 1000 women received during the course of pregnancy one or more prescriptions from the higher risk categories (D, C or B3) in the Australian system. By combining such utilization studies with data from registries of birth defects one will be able to develop the fund of knowledge and to ensure that the classification of drugs with respect to their risks in pregnancy is as accurate as it can reasonably be.